The present invention generally relates to box making machines which, for example, print on and/or slot, crease, or cut corrugated boards as they are conveyed along a horizontal path typically by rolls or endless belts. The boards are printed as they pass in the nip between a print cylinder and an impression cylinder. The print cylinder is equipped with printing dies or plates in the form of letters and/or numerals that form the indicia to be printed upon the boards in ink which is supplied to the print cylinder in any suitable manner typically by an ink roller.
Periodically an operator must access the print cylinder in order to change the print plates for another job to be run through the machine or simply to clean the print cylinder including the printing plates. This requires that the machine be stopped and the operator access the print cylinder. However in the typical box making machine this can be difficult if not awkward because the impression cylinder and the transportation mechanism such as feed or pull rolls are inhibiting if not blocking the desired access to the print cylinder.
In the typical, if not standard box making machine, the height of the path of conveyance of the boards is approximately forty-six inches (46″). In some machines of the prior art, this dimension has been raised to approximately 80″ in an effort to provide better access to the print cylinder depending on the type of transportation mechanism of the boards. However this type of machine requires platforms to allow the operators to access anything at boardline such as the feed table, requires that infeed and outfeed devices be elevated and requires that the print cylinder assembly be lowered to the operator for changeover and maintenance. Operator platforms present a hazard to safety while also encumbering the infeed and outfeed areas of the machines. Furthermore they do not alleviate the problem when certain transport mechanisms are being used by the machine. In addition, increasing or decreasing the height of the conveyance path detracts from the ability to accommodate some auxiliary equipment which is fitted for use with standard machines utilizing a conveyance path of forty-six inches.
Some other machines in the prior art use pits in the ground below the machine to allow the print cylinder to be accessed by the operator for setting up printing plates for a new job. However such pits present a safety hazard and while also attracting trash and other waste materials. They also encumber and increase the cost of the machine in the same way as other prior art machines. Furthermore the use of such machines is not adaptable to certain box making machines where the transportation mechanism and the impression cylinder are located in the same housing.
Other box making machines of the prior art are provided in sections that are horizontally movable along the path of conveyance between open positions providing access to the printing and impression cylinders for set-up, and closed positions for operating the machines. These machines increase the cost and require greater areas to accommodate them. The time required to allow an operator access to the print cylinders in these machines is significant as the entire machine must be opened one section at a time. In addition, they are not necessarily adaptable to box making machines whose transportation mechanisms are included in the same housing containing the impression cylinder.